Structural material, capable of withstanding halogen hydracids



Patented Dec. 19, 1933 STRUCTURAL MATERIAL, C A P A B L E OF WITHSTANDING HALOGEN HYDRACIDS Hermann Frischer, Berlin, Germany No Drawing.

Application November 24, 1931,

Serial No. 577,163, and in Great Britain October 2 Claims.

This invention relates to a structural material, capable of withstanding halogen hydracids.

It is known that in the arts, the structural materials employed (for the appliances used) in 6' the production, storage and cooling of halogen hydracids (especially hydrochloric acid and liquids containing same) consist almost exclusively of ceramic compositions. All the attempts hitherto made to employ for this purpose metals or 10 metallic alloys which, on the basis of laboratory experiments, were to be considered as proof against hydrochloric acid, have failed when employed in practice, either because these alloys lacked sumcient strength or have had to be composed of expensive metals which were out of the question as materials for the chemical industry. On the other hand, antimony, which is known to be capable of withstanding hydrochloric acid, cannot be employed, being too brittle. Moreover, the proposals already made to employ this metal alloyed with nickel--with addition of copper, molybdenum or tungsten, if desiredhave failed to make headway in the arts.

It has now been ascertained in accordance with the present invention that the aforesaid difliculties are avoided by alloying antimony with iron. This latter metal can, contrary to expectation, be alloyed with antimony, in any desired proportion, an addition of even less than 1% of iron increasing the mechanical strength of antimony to such an extent as to render it suitable as structural material for apparatus for the chemical industry, without such addition appreciably lowering its capacity for resisting the action of halogen hydracids. An important point as regards practical utility is that the iron in these alloys can be wholly or partially replaced by manganese, cobalt, molybdenum or tungsten, by which means these alloys can be modified so as to meet any dem sired requirements in respect of mechanical stress.

It for example, 02-05% of tungsten or molybdenum be incorporated in an iron-antimony alloy containing between 3 and 10% of iron, the mechanical strength of the alloy is still further in- 5 creased without impairing its resistance to the action of acids. If 1% of tungsten be incorporated into an antimony-iron alloy with to 96% of antimony and 304% of iron both the strength and powers of resistance of the alloy are improved by a further 20-30%. Similar efl'ects are produced by molybdenum.

Antimony-iron alloys containing up to 30% of iron completely withstand even hot technical hyo drochloric acid. Thus an antimony-iron alloy containing 2% of iron sustained a loss in weight of only 0.0750 grm. from a surface of 10 sq. cm. after exposure for 100 hours to the action. of crude hydrochloric acid 1:1 (about 17% of HCl) 5 at 75 C. Under the same experimental conditions, an antimony-iron alloy with 4% of iron sustained a loss in weight of only 0.0518 grm., and one with 8% of iron a loss of 0.0580 grms. whilst, under the same conditions, even an addition of 70 30% of iron resulted in a loss of only 0.0806 grm. in weight. It is thus evident that the iron content may be varied within a very wide range without impairing the power of withstanding hot hydrochloric acid. Moreover, the class of hydrochloric 75 acid may also vary within very wide limits. For example, an alloy of antimony with 4% of iron, after 24 hours exposure to a 10% acid at 30 (2., only lost 0.0048 grm. in weight, on a surface of 10 sq. cm., whilst the loss under the action of a 20% so acid was only 0.0030 grm. and in the case of 30% and 37% acid, only 0.0024 grm.

I claim:-

1. An alloy for use in chemical apparatus, the said alloy consisting of antimony and iron, the 35 iron present to the extent of 1 to 30% imparting mechanical strength to the alloy rendering it suitable as structural material for chemical ap-. paratus and the balance of the alloy in the form of antimony imparting thereto acid resistance which is not appreciably lowered by the presence of the iron.

2. An alloy for use in chemical apparatus, the said alloy consisting ofantimony and iron, the iron present to the extent of substantially 2% to 10% imparting mechanical strength to the alloy rendering it suitable as structural material for chemical apparatus and the balance of the alloy in the form of antimony imparting thereto acid resistance which is not appreciably lowered by the presence of the iron.

HERMANN narscnna. 

